Diseased or damaged cartilage has often been replaced by an artificial material, cadaver tissue, or donated, allogenic tissue. Tissue engineering offers an attractive alternative whereby a live, natural tissue is generated from a construct made up of a patient's own cells in combination with a biodegradable scaffold for replacement of defective tissue.
Cartilage defects resulting from aging, joint injury, and developmental disorders cause joint pain and loss of mobility. It would be desirable to provide a tissue engineering approach provides a cell-based therapy to repair articular cartilage defects and to restore joint functions. In prior attempts to tissue engineer cartilage, chondrocytes and mesenchymal stem cells (MSCs) have been used for cartilage regeneration, and the choice of cell type determines the strategy of cartilage tissue engineering in vitro.
Existing engineered cartilage and the methods of making same generate materials which do not possess the mechanical properties of natural cartilage. Thus, cartilage generated by seeding a hydrogel or preformed three dimensional polymeric scaffold are less resistant to compressive force than natural cartilage. Conventional methods of making cartilage, e.g., using a hydrogel or preformed three dimensional polymeric scaffold, result in despecification of the seeded chondocytes, poor intercellular contact between chondocytes, and/or insufficient mechanical strength.
The electrospinning process is a simple, economical means to produce supports or scaffolds of ultra-fine fibers derived from a variety of biodegradable polymers (Li W J, et al. J Biomed Mater Res 2002;60:613-21). Nanofibrous scaffolds (NFSs) formed by electrospinning, by virtue of structural similarity to natural extracellular matrix (ECM), may represent promising structures for tissue engineering applications. We have previously shown that electrospun three-dimensional NFSs are characterized by high porosity with a wide distribution of pore diameter, high-surface area to volume ratio, and morphological similarities to natural collagen fibrils (Li W J, et al., J Biomed Mater Res 2002;60:613-21). These physical characteristics promote favorable biological responses of seeded cells in vitro, including enhanced cell attachment, proliferation, and maintenance of the chondrocytic phenotype (Li W J, et al., J Biomed Mater Res 2002;60:613-21; and Li W J, et al. J Biomed Mater Res 2003;67A:1105-14).
It would be desirable to provide tissue engineered cartilage materials and methods of making same which are suitable for preparing cartilage suitable for use in repairing cartilage defects associated with degenerative joint diseases or in plastic/cosmetic surgery requiring repair or augmentation of cartilaginous tissue. More particularly, it would be desirable to provide methods of making high strength cartilage, tissue engineered cartilage prepared thereby and methods of treatment using such high strength tissue engineered cartilage.